Gate valve cleaning method and substrate processing system

ABSTRACT

A gate valve cleaning method that can clean a gate valve that brings an atmospheric transfer chamber and an internal pressure variable transfer chamber that transfer a substrate into communication with each other or shuts them off from each other without bringing about a decrease in the throughput of a substrate processing system. Before the gate valve brings the atmospheric transfer chamber and the internal pressure variable transfer chamber into communication with each other, the pressure in the internal pressure variable transfer chamber is increased so that the pressure in the internal pressure variable transfer chamber can become higher than the pressure in the atmospheric transfer chamber.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional of U.S. Ser. No. 11/969,428 filed Jan.4, 2008, the entire content of which is incorporated herein byreference. U.S. Ser. No. 11/969,428 is related to and claims priorityunder 35 U.S.C. §119(e) to U.S. provisional patent application No.60/896,940, filed Mar. 26, 2007 and claims priority under 35 U.S.C. 119to Japanese Application No. 2007-017047 filed Jan. 26, 2007.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a gate valve cleaning method and asubstrate processing system, and more particularly to a method ofcleaning a gate valve that brings an atmospheric transfer chamber and aninner pressure variable transfer chamber into communication with eachother or shuts them off from each other.

2. Description of the Related Art

A substrate processing system that subjects wafers as substrates toplasma processing is comprised of a process module that houses wafersand subjects them to plasma processing, a load-lock module thattransfers each wafer into the process module, and a loader module thatremoves each wafer from a container housing a plurality of wafers andtransfers the wafer to the load-lock module.

In general, the load-lock module of the substrate processing system hasa chamber in which a wafer is housed. The load-lock module has afunction of opening a gate valve on the loader module side, receiving awafer in the chamber at atmospheric pressure from a transfer chamber ofthe loader module, closing the gate valve on the loader module side,evacuating the interior of the chamber to a predetermined pressure,opening a gate valve on the process module side, transferring the waferinto the process module, transferring the wafer out of the processmodule upon completion of processing, closing the gate valve on theprocess module side, returning the pressure in the chamber toatmospheric pressure, opening the gate valve on the loader module side,and passing the wafer into the loader module (see, for example, JapaneseLaid-Open Patent Publication (Kokai) No. 2006-128578).

In the load-lock module, however, there may be a case where, in order toimprove the throughput of the substrate processing system or due to aproblem concerning accuracy of a pressure gauge, the gate valve on theloader module side is opened to pass a wafer without completelyreturning the pressure in the chamber to atmospheric pressure, i.e. whenthe pressure in the chamber is lower than the pressure (atmosphericpressure) in the transfer chamber of the loader module. In this case,the atmosphere in the transfer chamber of the loader module flows intothe chamber of the load-lock module.

Meanwhile, as shown in FIG. 8A, a conventional gate valve 70 that isdisposed between a loader module and a load-lock module and is openedand closed so that the loader module and the load-lock module can bebrought into communication with each other or shut off from each otheris comprised of a wafer transfer port 71, and a valve element 72 that isdriven vertically as viewed in FIG. 8A by a valve element drivingmechanism (not shown) so as to open and close the wafer transfer port71.

In the gate valve 70, in opening and closing the wafer transfer port 71via the valve element 72, particles 74 produced through rubbing of thevalve element 72 against a member 73 that defines the wafer transferport 71 become attached to, in particular, the valve element 72 (FIG.8B). As a result, as described above, when the wafer transfer port 71 isopened via the valve element 72 when the pressure in the load-lockmodule is lower than the pressure in the transfer chamber (atmosphericpressure) of the loader module, the atmosphere inside the loader moduleflows into the chamber of the load-lock module (FIG. 8C), and theparticles 74 attached to the valve element 72 are scattered awaythrough, for example, a disturbance caused by viscous force of theatmosphere, and the scattered particles 74 enter into the chamber of theload-lock module (FIG. 8D). The particles 74 having entered into thechamber of the load-lock module become attached to and accumulated onsurfaces of wafers to be transferred, and the particles 74 attached toand accumulated on the wafer cause defects of patterns formed on thewafers. Thus, if the particles 74 enter into the chamber of theload-lock module, the yield and reliability of devices ultimatelymanufactured from the wafers are decreased.

Conventionally, to prevent the particles 74 from entering into thechamber of the load-lock module, the particles 74 attached to the gatevalve 70, in particular, the valve element 72 have been removed inadvance through cleaning such as wiping by an operator. However,operation of the substrate processing system has to be stopped for anoperator to carry out cleaning such as wiping, and this hassignificantly decreased the throughput of the substrate processingsystem.

SUMMARY OF THE INVENTION

The present invention provides a gate valve cleaning method and asubstrate processing system that can clean a gate valve, which brings anatmospheric transfer chamber and an internal pressure variable transferchamber that transfer a substrate into communication with each other orshuts them off from each other, without bringing about a decrease in thethroughput of the substrate processing apparatus.

Accordingly, in a first aspect of the present invention, there isprovided a method of cleaning a gate valve in a substrate processingsystem including the gate valve that brings an atmospheric transferchamber and an internal pressure variable transfer chamber that transfera substrate into communication with each other or shuts off theatmospheric transfer chamber and the internal pressure variable transferchamber from each other, comprising a pressure increasing step of,before the gate valve brings the atmospheric transfer chamber and theinternal pressure variable transfer chamber into communication with eachother, increasing a pressure in the internal pressure variable transferchamber so that the pressure in the internal pressure variable transferchamber becomes higher than a pressure in the atmospheric transferchamber.

According to the first aspect of the present invention, before the gatevalve brings the atmospheric transfer chamber and the internal pressurevariable transfer chamber into communication with each other, thepressure in the internal pressure variable transfer chamber is increasedso that the pressure in the internal pressure variable transfer chamberbecomes higher than the pressure in the atmospheric transfer chamber.Thus, after the pressure in the internal pressure variable transferchamber becomes higher than the pressure in the atmospheric transferchamber, the gate valve brings the atmospheric transfer chamber and theinternal pressure variable transfer chamber into communication with eachother. If foreign matter is attached to the gate valve, the foreignmatter is scattered away through, for example, a disturbance caused byviscous force of an internal gas that has flowed from the internalpressure variable transfer chamber into the atmospheric transfer chamberwhen the atmospheric transfer chamber and the internal pressure variabletransfer chamber are brought into communication with each other, and thescattered foreign matter enters into the atmospheric transfer chamber.Air flowing into the atmospheric transfer chamber through a ceilingportion thereof flows out through a bottom portion thereof. Thus, theentered foreign matter as well as air flowing in are caused to flow outfrom the interior of the substrate processing system. As a result, theforeign matter attached to the gate valve can be removed, and theforeign matter can be discharged from the interior of the substrateprocessing system. Therefore, even when air in the atmospheric transferchamber flows into the internal pressure variable transfer chamber,since foreign matter attached to the gate valve has already beenremoved, the foreign matter can be prevented from entering into theinternal pressure variable transfer chamber, and this enables the yieldand reliability of semiconductor devices ultimately manufactured to beincreased. Further, since foreign matter attached to the gate valve canbe removed without the need to carry out cleaning such as wiping by anoperator, i.e. without stopping operation of the substrate processingsystem, the gate valve that brings the atmospheric transfer chamber andthe internal pressure variable transfer chamber into communication witheach other or shuts them off from each other can be cleaned withoutbringing about a decrease in the throughput of the substrate processingsystem.

Accordingly, in a second aspect of the present invention, there isprovided a method of cleaning a gate valve in a substrate processingsystem including the gate valve that comprises a communication port thatbrings an atmospheric transfer chamber and an internal pressure variabletransfer chamber that transfer a substrate into communication with eachother and a valve element that opens and closes the communication port,comprising a jetting step of jetting out a removal promoting substancethat promotes removal of foreign matter attached to the gate valvetoward the valve element from the internal pressure variable transferchamber side.

According to the second aspect of the present invention, a removalpromoting substance that promotes removal of foreign matter attached tothe gate valve is jetted out from the internal pressure variabletransfer chamber side toward the valve element that opens and closes thecommunication port. If foreign matter is attached to the valve element,removal of the foreign matter is promoted by the jetted removalpromoting substance so that the foreign matter is scattered away, andthe scattered foreign matter enters into the atmospheric transferchamber. Air flowing into the atmospheric transfer chamber through aceiling portion thereof flows out through a bottom portion thereof.Thus, the entered foreign matter as well as air flowing in are caused toflow out from the interior of the substrate processing system. As aresult, the foreign matter attached to the gate valve, in particular,the valve element can be removed, and the foreign matter can bedischarged from the interior of the substrate processing system.Therefore, even when air in the atmospheric transfer chamber flows intothe internal pressure variable transfer chamber, since foreign matterattached to the gate valve, in particular, the valve element has alreadybeen removed, the foreign matter can be prevented from entering into theinternal pressure variable transfer chamber, and this enables the yieldand reliability of semiconductor devices ultimately manufactured to beincreased. Further, since foreign matter attached to the gate valve, inparticular, the valve element can be removed without the need to carryout cleaning such as wiping by an operator, i.e. without stoppingoperation of the substrate processing system, the gate valve that bringsthe atmospheric transfer chamber and the internal pressure variabletransfer chamber into communication with each other or shuts them offfrom each other can be cleaned without bringing about a decrease in thethroughput of the substrate processing system.

The present invention can provide a cleaning method, wherein the removalpromoting substance comprises a high-temperature gas.

According to the second aspect of the present invention, the removalpromoting substance is comprised of a high-temperature gas. Therefore,if foreign matter including fine foreign matter is attached to the valveelement, the foreign matter can be scattered away through, for example,a disturbance caused by viscous force and thermal stress of thehigh-temperature gas.

The present invention can provide a cleaning method, wherein the removalpromoting substance comprises a vibration gas.

According to the second aspect of the present invention, the removalpromoting substance is comprised of a vibration gas. Therefore, ifforeign matter is attached to the valve element, the foreign matter canbe reliably scattered away through, for example, a disturbance caused byviscous force of the vibration gas and a strong physical collision ofmolecules in the vibration gas.

The present invention can provide a cleaning method, wherein the removalpromoting substance comprises a mixture of a first substance in gaseousform and a second substance in one of liquid form and solid form.

According to the second aspect of the present invention, the removalpromoting substance is comprised of a mixture of a first substance ingaseous form and a second substance in one of liquid form and solidform. Therefore, if foreign matter is attached to the valve element, theforeign matter can be reliably scattered away through, for example, adisturbance caused by viscous force of the mixture and a physicalcollision of the second substance in liquid or solid form in themixture.

The present invention can provide a cleaning method, wherein thesubstrate processing system comprises a single-pole electrode platedisposed closer to the atmospheric transfer chamber than the valveelement, and the removal promoting substance comprises a single-pole ionadded gas formed by adding single-pole ions of a reverse polarity to apolarity of the single-pole electrode plate to a gas.

According to the second aspect of the present invention, the removalpromoting substance is comprised of a single-pole ion added gas formedby adding single-pole ions of the reverse polarity to the polarity ofthe single-pole electrode plate, which is disposed closer to theatmospheric transfer chamber than the valve element, to a gas.Therefore, if foreign matter is attached to the valve element, theforeign matter can be reliably scattered away through, for example, adisturbance caused by viscous force of the single-pole ion added gas andattraction for the single-electrode plate caused by an electrostaticforce produced through charging the foreign matter on the reversepolarity to the polarity of the single-pole electrode plate due to aphysical collision of single-pole ions in the single-pole ion added gas.

The present invention can provide a cleaning method, wherein the valveelement is electrically charged, and the removal promoting substancecomprises single-pole ions of a reverse polarity to a polarity of thevalve element.

According to the second aspect of the present invention, the removalpromoting substance is comprised of single-pole ions of the reversepolarity to the polarity of the valve element. Therefore if foreignmatter including fine foreign matter is attached to the valve element,the foreign matter can be reliably scattered away through sputteringcaused by the single-pole ions.

The present invention can provide a cleaning method, wherein the removalpromoting substance comprises radicals or a highly-reactive gas.

According to the second aspect of the present invention, the removalpromoting substance is comprised of radicals or a highly-reactive gas.Therefore, if foreign matter including fine foreign matter is attachedto the valve element, the foreign matter can be scattered away throughchemical reaction with the radicals or a highly-reactive substanceincluded in the highly-reactive gas.

Accordingly, in a third aspect of the present invention, there isprovided a substrate processing system including a gate valve thatbrings an atmospheric transfer chamber and an internal pressure variabletransfer chamber that transfer a substrate into communication with eachother or shuts off the atmospheric transfer chamber and the internalpressure variable transfer chamber from each other, comprising apressure increasing mechanism adapted to increase a pressure in theinternal pressure variable transfer chamber so that the pressure in theinternal pressure variable transfer chamber becomes higher than apressure in the atmospheric transfer chamber before the gate valvebrings the atmospheric transfer chamber and the internal pressurevariable transfer chamber into communication with each other.

Accordingly, in a fourth aspect of the present invention, there isprovided a substrate processing system including a gate valve thatcomprises a communication port that brings an atmospheric transferchamber and an internal pressure variable transfer chamber that transfera substrate into communication with each other and a valve element thatopens and closes the communication port, comprising a jetting mechanismadapted to jet out a removal promoting substance that promotes removalof foreign matter attached to the gate valve toward the valve elementfrom the internal pressure variable transfer chamber side.

The present invention can provide a substrate processing system, whereinthe jetting mechanism comprises a removal promoting substance generatingunit adapted to generate the removal promoting substance by heating agas.

The present invention can provide a substrate processing system, whereinthe jetting mechanism comprises a removal promoting substance generatingunit adapted to generate the removal promoting substance by applying avibration to a gas.

The present invention can provide a substrate processing system, whereinthe vibration comprises an ultrasonic wave.

According to the fourth aspect of the present invention, the vibrationgas is produced by applying an ultrasonic wave to a gas. Therefore,vibrations can be reliably applied to a gas.

The present invention can provide a substrate processing system, whereinthe jetting mechanism comprises a removal promoting substance generatingunit adapted to generate the removal promoting substance by mixing afirst substance in gaseous form and a second substance in one of liquidform and solid form.

The present invention can provide a substrate processing system,comprising a single-pole electrode plate disposed closer to theatmospheric transfer chamber than the valve element, and wherein thejetting mechanism comprises a removal promoting substance generatingunit adapted to generate the removal promoting substance by addingsingle-pole ions of a reverse polarity to a polarity of the single-poleelectrode plate to a gas.

The present invention can provide a substrate processing system, whereinthe jetting mechanism comprises a removal promoting substance generatingunit adapted to generate the removal promoting substance by turning agas into plasma.

According to the fourth aspect of the present invention, the removalpromoting substance is comprised of ions and radicals produced byturning a gas into plasma. Therefore, if foreign matter including fineforeign matter is attached to the valve element, the ions and radicalscan promote removal of the foreign matter so that the foreign matter isscattered away.

The present invention can provide a substrate processing system, furthercomprising a charging mechanism adapted to electrically charge the valveelement.

According to the fourth aspect of the present invention, the valveelement is electrically charged. Therefore, if foreign matter includingfine foreign matter is attached to the valve element, the foreign mattercan be reliably scattered away through sputtering with ions of thereverse polarity to the polarity of the valve element.

The present invention can provide a substrate processing system, whereinthe valve element has therein one of a coil, a heater, and an electrodeplate.

According to the fourth aspect of the present invention, the valveelement has therein one of a coil, a heater, and an electrode plate. Ifthe valve element has a coil therein, by passing a current through thecoil from a direct-current power source, an induced electric field isproduced around the valve element. As a result, an electromagneticstress as a repulsive force that separates foreign matter from the valveelement can be caused to act on the foreign matter attached to the valveelement, and hence removal of the foreign matter can be promoted. If thevalve element has therein a heater, the heater heats the valve element.As a result, a thermal stress as a removal force that removes foreignmatter from the valve element can be caused to act on the foreign matterattached to the valve element, and hence removal of the foreign mattercan be promoted. If the valve element has therein an electrode plate, acurrent is passed through the electrode plate from a direct-currentpower source. As a result, an electrostatic force as a repulsive forcethat separates foreign matter from the valve element can be caused toact on the foreign matter attached to the valve element, and henceremoval of the foreign matter can be promoted.

The present invention can provide a substrate processing system, furthercomprising at least one of a first suction mechanism disposed closer tothe atmospheric transfer chamber than the valve element, and a secondsuction mechanism disposed closer to the internal pressure variabletransfer chamber than the valve element.

According to the fourth aspect of the present invention, there is atleast one of a first suction mechanism disposed closer to theatmospheric transfer chamber than the valve element, and a secondsuction mechanism disposed closer to the internal pressure variabletransfer chamber than the valve element. The first suction mechanism orthe second suction mechanism sucks foreign matter scattered away fromthe valve element. As a result, the scattered foreign matter can bereliably discharged from the interior of the substrate processingsystem.

The present invention can provide a substrate processing system, whereinthe jetting mechanism comprises a nozzle.

According to the fourth aspect of the present invention, the removalpromoting substance is jetted out from a nozzle. Therefore, the removalpromoting substance can be reliably jetted out toward the valve element.

The features and advantages of the invention will become more apparentfrom the following detailed description taken in conjunction with theaccompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a sectional view schematically showing the construction of asubstrate processing system according to a first embodiment of thepresent invention;

FIGS. 2A and 2B are process drawings of a cleaning process carried outin the substrate processing system according to the first embodiment;

FIGS. 3A and 3B are process drawings of a cleaning process carried outin a substrate processing system according to a second embodiment of thepresent invention;

FIGS. 4A and 4B are process drawings of a cleaning process carried outin a first variation of the substrate processing system according to thesecond embodiment;

FIGS. 4C and 4D are process drawings of a cleaning process carried outin a second variation of the substrate processing system according tothe second embodiment;

FIGS. 5A and 5B are process drawings of a cleaning process carried outin a third variation of the substrate processing system according to thesecond embodiment;

FIGS. 5C and 5D are process drawings of a cleaning process carried outin a fourth variation of the substrate processing system according tothe second embodiment;

FIGS. 6A and 6B are process drawings of a cleaning process carried outin a fifth variation of the substrate processing system according to thesecond embodiment;

FIGS. 6C and 6D are process drawings of a cleaning process carried outin a sixth variation of the substrate processing system according to thesecond embodiment;

FIG. 7A is a sectional view schematically showing the construction of avariation of the substrate processing systems according to theabove-mentioned embodiments and shows a case where a valve element has acoil therein;

FIG. 7B is a sectional view schematically showing the construction of avariation of the substrate processing systems according to theabove-mentioned embodiments and shows a case where the valve element hasa heater therein;

FIG. 7C is a sectional view schematically showing the construction of avariation of the substrate processing systems according to theabove-mentioned embodiments and shows a case where the valve element hasan electrode plate therein;

FIG. 7D is a sectional view schematically showing the construction of avariation of the substrate processing systems according to theabove-mentioned embodiments and shows a case where there is a suctionnozzle; and

FIGS. 8A to 8D are sectional views useful in explaining the constructionand operation of a conventional gate valve.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention will now be described with reference to theaccompanying drawings showing preferred embodiments thereof.

First, a description will be given of a substrate processing systemaccording to a first embodiment of the present invention.

FIG. 1 is a sectional view schematically showing the construction of thesubstrate processing system according to the first embodiment.

As shown in FIG. 1, the substrate processing system 1 is comprised of aprocess module 2 that subjects semiconductor wafers (hereinafterreferred to merely as “wafers”) W as substrates to various plasmaprocessing such as deposition, diffusion, and etching, a loader module 4that removes each wafer W from a wafer cassette 3 housing apredetermined number of wafers W, and a load-lock module 5 that isdisposed between the loader module 4 and the process module 2 and is fortransferring each wafer W from the loader module 4 into the processmodule 2 and from the process module 2 into the loader module 4.

Each of the process module 2 and the load-lock module 5 is constructedsuch that the interior thereof can be evacuated, while the interior ofthe loader module 4 is always held at atmospheric pressure. The processmodule 2 and the load-lock module 5 are connected together via a gatevalve 6, and the load-lock module 5 and the loader module 4 areconnected together via a gate valve 7, described later. Moreover, theinterior of the load-lock module 5 and the interior of the loader module4 are in communication with each other via a communicating pipe 9 havingan openable/closable valve 8 disposed part way therealong.

The process module 2 has therein a cylindrical chamber 10 made of metalsuch as aluminum or stainless steel, and a cylindrical susceptor 11 as amounting stage on which is mounted a wafer W having a diameter of, forexample, 300 mm is disposed in the chamber 10.

An exhaust path 12 that acts as a flow path through which gas in aprocessing space S, described later, is discharged to the outside of thechamber 10 is formed between the side wall of the chamber 10 and thesusceptor 11. An annular exhaust plate 13 is disposed part way along theexhaust path 12, and a manifold 14 as a space downstream of the exhaustplate 13 communicates with an adaptive pressure control valve (APCvalve) 15, which is a variable butterfly valve. The APC valve 15 isconnected to a turbo-molecular pump (TMP) 16, which is an exhaustingpump for evacuation. The exhaust plate 13 prevents leakage of plasmagenerated in the processing space into the manifold 14. The APC valve 15controls the pressure in the chamber 10, and the TMP 16 reduces thepressure in the chamber 10 down to a substantially vacuum state.

A radio frequency power source 17 is connected to the susceptor 11 via amatcher 18. The radio frequency power source 17 supplies radio frequencyelectrical power into the susceptor 11. The susceptor 11 thus acts as alower electrode. The matcher 18 reduces reflection of the radiofrequency electrical power from the susceptor 11 so as to maximize theefficiency of the supply of the radio frequency electrical power intothe susceptor 11.

An electrode plate (not shown) for attracting a wafer W through aJohnsen-Rahbek force or a Coulomb force is disposed in the susceptor 11.The wafer W is thus attracted to and held on an upper surface of thesusceptor 11. Moreover, an annular focus ring 19 is provided on an upperportion of the susceptor 11 made of silicon or the like and focusesplasma in the processing space S between the susceptor 11 and a showerhead 20, descried later, toward the wafer W.

An annular coolant chamber (not shown) is provided inside the susceptor11. A coolant, for example, cooling water, at a predeterminedtemperature is circulated through the coolant chamber, so that thetemperature of the wafer W being processed on the susceptor 11 iscontrolled through the temperature of the coolant. It should be notedthat helium gas is supplied into a gap between the wafer W and thesusceptor 11 and transmits heat of the wafer W to the susceptor 11.

The disk-shaped shower head 20 is disposed in a ceiling portion of thechamber 10. A radio frequency power source 21 is connected to the showerhead 20 via a matcher 22. The radio frequency power source 21 suppliesradio frequency electrical power into the shower head 20. The showerhead 20 thus acts as an upper electrode. The matcher 22 has a similarfunction to the matcher 18.

A processing gas introducing pipe 23 that supplies a processing gas, forexample, a mixed gas of a CF-based gas and other type of gas isconnected to the shower head 20. The shower head 20 introduces theprocessing gas supplied from the processing gas introducing pipe 23 intothe processing space S.

In the chamber 10 of the process module 2, the susceptor 11 and theshower head 20 to which radio frequency electrical power is suppliedapplies the radio frequency electrical power into the processing spaceS, whereby the processing gas is turned into high-density plasma in theprocessing space S. The plasma is focused onto the surface of the waferW by the focus ring 19, whereby the surface of the wafer W isphysically/chemically etched.

The loader module 4 has a wafer cassette mounting stage 24 on which thewafer cassette 3 is mounted, and a transfer chamber 25 (atmospherictransfer chamber). The wafer cassette 3 houses, for example, 25 wafersW, which are mounted in a plurality of tiers at equal pitch. Thetransfer chamber 25 has a rectangular parallelepiped box shape, and hastherein a SCARA-type transfer arm 26 for transferring the wafers W.

The transfer arm 26 has an articulated transfer arm arm portion 27 whichis constructed such as to be able to bend and extend, and a pick 28attached to a distal end of the transfer arm arm portion 27. The pick 28is constructed such that a wafer W is mounted directly thereon.Moreover, the transfer arm 26 is constructed such as to be able to turnand can be freely bent by the transfer arm arm portion 27, and hence awafer W mounted on the pick 28 can be freely transferred between thewafer cassette 3 and the load-lock module 5.

An inflow pipe 29 through which air flows into the transfer chamber 25is connected to a ceiling portion of the transfer chamber 25, and anoutflow pipe 30 through which air in the transfer chamber 25 flows outis connected to a bottom portion of the transfer chamber 25. Therefore,air flowing in from the ceiling portion of the transfer chamber 25 flowsout from the bottom portion of the transfer chamber 25. Thus, airflowing into the transfer chamber 25 forms a down flow.

The load-lock module 5 has a chamber 32 (internal pressure variabletransfer chamber) in which is disposed a transfer arm 31 that can bend,extend and turn, a gas supply system 33 (lifting mechanism) thatsupplies an inert gas such as N₂ gas into the chamber 32, and aload-lock module exhaust system 34 that exhausts the interior of thechamber 32. The transfer arm 31 is a SCARA-type transfer arm comprisinga plurality of arm portions, and has a pick 35 attached to a distal endthereof. The pick 35 is constructed such that a wafer W is mounteddirectly thereon.

When a wafer W is to be transferred from the loader module 4 into theprocess module 2, once the gate valve 7 has been opened, the transferarm 31 receives the wafer W from the transfer arm 26 in the transferchamber 25, and once the gate valve 6 has been opened, the transfer arm31 enters into the chamber 10 of the process module 2 and mounts thewafer W on the susceptor 11. Moreover, when the wafer W is to betransferred from the process module 2 into the loader module 4, once thegate valve 6 has been opened, the transfer arm 31 enters into thechamber 10 of the process module 2 and receives the wafer W from thesusceptor 11, and once the gate valve 7 has been opened, the transferarm 31 passes the wafer W to the transfer arm 26 in the transfer chamber25.

As shown in FIG. 2A, the gate valve 7 is comprised of a wafer transferport 36 (communicating port), and a valve element 37 that is drivenvertically as viewed in FIG. 2A by a valve element driving mechanism(not shown) to open and close the wafer transfer port 36. The gate valve7 brings the loader module 4 and the load-lock module 5 intocommunication with each other by opening the wafer transport port 36with the valve element 37 and shuts them off from each other by closingthe wafer transport port 36 with the valve element 37.

In the gate valve 7, when the valve element 37 opens and closes thewafer transfer port 36, particles P produced through rubbing of thevalve element 37 against a member 38 that defines the wafer transferelement 36 become attached to, in particular, the valve element 37.

In the substrate processing system according to the present embodiment,particles P attached to the gate valve 7, in particular, the valveelement 37 are removed by carrying out a cleaning process, describedlater.

It should be noted that operation of the component elements of theprocess module 2, the loader module 4, and the load-lock module 5constituting the substrate processing system 1 is controlled by acomputer (not shown) as a controller of the substrate processing system1, or by an external server (not shown) as a controller connected to thesubstrate processing system 1.

Next, a description will be given of the cleaning process carried out inthe substrate processing system according to the present embodiment.

FIGS. 2A and 2B are process drawings of the cleaning process carried outin the substrate processing system according to the present embodiment.

As shown in FIGS. 2A and 2B, before the valve element 37 opens the wafertransfer port 36 so as to bring the loader module 4 and the load-lockmodule 5 into communication with each other, the gas supply system 33supplies an inert gas such as N₂ gas into the chamber 32 of theload-lock module 5 so that the pressure in the chamber 32 can becomehigher than the pressure (atmospheric pressure) in the transfer chamber25 of the loader module 4 (FIG. 2A) (pressure increasing step).

Then, when the valve element 37 opens the wafer transfer port 36 afterthe pressure in the chamber 32 of the load-lock module 5 becomes higherthan the pressure (atmospheric pressure) in the transfer chamber 25 ofthe loader module 4, the inert gas such as N₂ gas in the chamber 32 ofthe load-lock module 5 flows into the transfer chamber 25 of the loadermodule 4, and particles P attached to the valve element 37 are scatteredaway through, for example, a disturbance caused by viscous force of theinert gas such as N₂ gas that has flowed in, and the scattered particlesP enter into the transfer chamber 25 of the loader module 4 (FIG. 2B).Since air flowing into the transfer chamber 25 from the ceiling portionthereof flows out from the bottom portion thereof, the particles P aswell as the air flowing in from the ceiling portion are caused to flowout from the bottom portion. Thus, the particles P attached to the valveelement 37 can be removed, and the particles P can be discharged fromthe interior of the substrate processing system 1.

According to the cleaning process described above with reference toFIGS. 2A and 2B, after the gas supply system 33 supplies an inert gassuch as N₂ gas into the chamber 32 of the load-lock module 5 so that thepressure in the chamber 32 can become higher than the pressure(atmospheric pressure) in the transfer chamber 25 of the loader module4, the valve element 37 opens the wafer transfer port 36. If particles Pare attached to the valve element 37, the particles P are scattered awaythrough, for example, a disturbance caused by viscous force of the inertgas such as N₂ gas that has flowed in when the wafer transfer port 36 isopened, the scattered particles P enter into the transfer chamber 25 ofthe loader module 4, and the particles P as well as air flowing into thetransfer chamber 25 are caused to flow out from the interior of thesubstrate processing system 1. Thus, the particles P attached to thegate valve 7, in particular, the valve element 37 can be removed, andthe particles P can be discharged from the interior of the substrateprocessing system 1. Therefore, even when air in the transfer chamber 25of the loader module 5 flows into the chamber 32 of the load-lock module5, since particles P attached to the gate valve 7, in particular, thevalve element 37 have already been removed, the particles P can beprevented from entering into the chamber 32 of the load-lock module 5,and this enables the yield and reliability of semiconductor devicesultimately manufactured to be increased. Further, since particles Pattached to the gate valve 7, in particular, the valve element 37 can beremoved without the need to carry out cleaning such as wiping by anoperator, i.e. without stopping operation of the substrate processingsystem 1, the gate valve 7 that brings the loader module 4 and theload-lock module 5 into communication with each other or shuts them offfrom each other can be cleaned without bringing about a decrease in thethroughput of the substrate processing system 1.

Next, a description will be given of a substrate processing systemaccording to a second embodiment of the present invention.

The present embodiment is basically the same as the first embodimentdescribed above in terms of construction and operation, differing fromthe first embodiment in the construction of the gate valve disposedbetween the loader module and the load-lock module. Thus, features ofthe construction and operation that are the same as in the firstembodiment will not be described, only features different from those ofthe first embodiment being described below.

As shown in FIG. 3A, a gate valve 39 that is disposed between the loadermodule 4 and the load-lock module 5 and brings them into communicationwith each other or shuts them off from each other has a nozzle 40(jetting mechanism) penetrating from outside through the member 38 thatdefines the wafer transfer port 36 and having a distal end thereofprojecting out into the wafer transfer port 36 and bending toward thevalve element 37. The nozzle 40 jets out a gas (removal promotingsubstance) that promotes removal of particles P attached to the gatevalve 39, in particular, the valve element 37 toward the valve element37.

Next, a description will be given of a cleaning process carried out inthe substrate processing system according to the present embodiment.

FIGS. 3A and 3B are process drawings of the cleaning process carried outin the substrate processing system according to the present embodiment.

As shown in FIGS. 3A and 3B, first, before a wafer W is transferred inthe substrate processing system, the nozzle 40 jets out theabove-described gas toward the valve element 37 (FIG. 3A).

Then, particles P attached to the valve element 37 are scattered awaythrough a disturbance caused by viscous force of the jetted gas, and thescattered particles P enter into the transfer chamber 25 of the loadermodule 4 (FIG. 3B).

According to the cleaning process of FIGS. 3A and 3B described above,before a wafer W is transferred, the nozzle 40 jets out the gas thatpromotes removal of particles P attached to the gate valve 39, inparticular, the valve element 37 toward the valve element 37. Ifparticles P are attached to the valve element 37, the particles Pattached to the valve element 37 are scattered away through adisturbance caused by viscous force of the jetted gas, the scatteredparticles P enter into the transfer chamber 25 of the loader module 4,and the particles P having entered into the transfer chamber 25 as wellas air flowing into the transfer chamber 25 are caused to flow out fromthe interior of the substrate processing system. Thus, the particles Pattached to the gate valve 39, in particular, the valve element 37 canbe removed, and the particles P can be discharged from the interior ofthe substrate processing system.

Moreover, in the process of FIGS. 3A and 3B described above, the nozzle40 may jet out the above-described gas toward the valve element 37 atregular intervals. The gas jet out at regular intervals turns into shockwaves. Conventionally, upon attempting to scatter away particles such asfine particles attached to a valve element through a disturbance causedby viscous force of a jetted gas, a layer where the flow velocity of thegas is zero (a boundary layer) has arisen on the surface of the valveelement, and hence it has been difficult for the gas to reach fineparticles within the boundary layer, and thus it has not been possibleto efficiently scatter away the fine particles. In contrast with this,in the present embodiment, since the shock waves can break through theabove-described boundary layer, particles P including fine particlesattached to the valve element 37 are scattered away through adisturbance caused by a collision with gas molecules. Thus, theparticles P including fine particles attached to the valve element 37can be efficiently removed.

Next, a description will be given of cleaning processes carried out invariations of the substrate processing system according to the presentembodiment.

FIGS. 4A and 4B are process drawings of a cleaning process carried outin a first variation of the substrate processing system according to thepresent embodiment. In this variation, the nozzle 40 has a heating unit41 (removal promoting substance generating unit) disposed part waytherealong, for heating a gas to produce a high-temperature gas (removalpromoting substance).

As shown in FIGS. 4A and 4B, first, before a wafer W is transferred inthe substrate processing system, the nozzle 40 jets out ahigh-temperature gas produced by the heating unit 41 toward the valveelement 37 (FIG. 4A).

Then, particles P including fine particles attached to the valve element37 are scattered away through a disturbance caused by viscous force andthermal stress of the jetted high-temperature gas, and the scatteredparticles P enter into the transfer chamber 25 of the loader module 4(FIG. 4B).

According to the cleaning process of FIGS. 4A and 4B described above,before the wafer W is transferred, the nozzle 40 jets out thehigh-temperature gas produced by the heating unit 41 toward the valveelement 37. If particles P including fine particles are attached to thevalve element 37, the particles P are scattered away through, forexample, a disturbance caused by viscous force and thermal stress of thejetted high-temperature gas, the scattered particles P enter into thetransfer chamber 25 of the loader module 4, and the particles P havingentered into the transfer chamber 25 as well as air flowing into thetransfer chamber 25 are caused to flow out from the interior of thesubstrate processing system. Thus, the particles P including fineparticles attached to the gate valve 39, in particular, the valveelement 37 can be removed, and the particles P can be discharged fromthe interior of the substrate processing system.

It should be noted that in the present variation, since thehigh-temperature gas is jetted out toward the valve element 37, thevalve element 37 must have heat resistance. Accordingly, rubber withheat resistance having few double links or no double links in a mainchain of rubber molecules such as a heat-resistant fluoro rubber O-ring,a FLID O-ring, a FLID ARMOR O-ring, a SPOQ ARMOR O-ring, a HYREC ARMORO-ring, an ULTIC ARMOR O-ring, or a LABE ARMOR O-ring is used as anO-ring for the valve element 37 according to the temperature of thehigh-temperature gas.

FIGS. 4C and 4D are process drawings of a cleaning process carried outin a second variation of the substrate processing system according tothe present embodiment. In this variation, the nozzle 40 has anultrasonic wave applying unit 42 (removal promoting substance generatingunit) disposed part way therealong, for applying an ultrasonic wave to agas to produce a vibration gas (removal promoting substance).

As shown in FIGS. 4C and 4D, first, before a wafer W is transferred inthe substrate processing system, the nozzle 40 jets out a vibration gasproduced by the ultrasonic wave applying unit 42 toward the valveelement 37 (FIG. 4C).

Then, particles P attached to the valve element 37 are reliablyscattered away through, for example, a disturbance caused by viscousforce of the vibration gas and a strong physical collision of moleculesin the vibration gas, and the scattered particles P enter into thetransfer chamber 25 of the loader module 4 (FIG. 4D).

According to the cleaning process of FIGS. 4C and 4D described above,before the wafer W is transferred, the nozzle 40 jets out the vibrationgas produced by the ultrasonic wave applying unit 42 toward the valveelement 37. If particles P are attached to the valve element 37, theparticles P are reliably scattered away through, for example, adisturbance caused by viscous force of the vibration gas and a strongphysical collision of molecules in the vibration gas, the scatteredparticles P enter into the transfer chamber 25 of the loader module 4,and the particles P having entered into the transfer chamber 25 as wellas air flowing into the transfer chamber 25 are caused to flow out fromthe interior of the substrate processing system. Thus, the particles Pattached to the gate valve 39, in particular, the valve element 37 canbe reliably removed, and the particles P can be discharged from theinterior of the substrate processing system.

Although in the present variation, the vibration gas is produced byapplying an ultrasonic wave to a gas, the vibration gas may be producedby applying a sound wave with a lower frequency than an ultrasonic waveto a gas.

FIGS. 5A and 5B are process drawings of a cleaning process carried outin a third variation of the substrate processing system according to thepresent embodiment. In this variation, the nozzle 40 has a mixing unit43 (removal promoting substance generating unit) disposed part waytherealong, for mixing a first substance in gaseous form and a secondsubstance in liquid or solid form to produce an aerosol (removalpromoting substance or mixture). It should be noted that the secondsubstance is preferably a substance that vaporizes at room temperature,e.g. carbon dioxide or argon.

As shown in FIGS. 5A and 5B, first, before a wafer W is transferred inthe substrate processing system, the nozzle 40 jets out an aerosolproduced by the mixing unit 43 toward the valve element 37 (FIG. 5A).

Then, particles P including fine particles attached to the valve element37 are reliably scattered away through, for example, a disturbancecaused by viscous force of the jetted aerosol and a physical collisionof the second substance in liquid or solid form in the aerosol, and thescattered particles P enter into the transfer chamber 25 of the loadermodule 4 (FIG. 5B).

According to the cleaning process of FIGS. 5A and 5B described above,before the wafer W is transferred, the nozzle 40 jets out the aerosolproduced by the mixing unit 43 toward the valve element 37. If particlesP are attached to the valve element 37, the particles P are reliablyscattered away through, for example, a disturbance caused by viscousforce of the jetted aerosol and a strong physical collision of thesecond substance in liquid or solid form, the scattered particles Penter into the transfer chamber 25 of the loader module 4, and theparticles P having entered into the transfer chamber 25 as well as airflowing into the transfer chamber 25 are caused to flow out from theinterior of the substrate processing system. Thus, the particles Pincluding fine particles attached to the gate valve 39, in particular,the valve element 37 can be reliably removed, and the particles P can bedischarged from the interior of the substrate processing system.

Although in the present variation, the aerosol is produced by mixing thefirst substance in gaseous form and the second substance in liquid orsolid form, a substance in gaseous form having a high melting point maybe jetted out from the nozzle 40 and turned into an aerosol usingtemperature decrease caused by adiabatic expansion occurring at the timeof jetting. Also, a substance in gaseous form having a high meltingpoint may be turned into an aerosol by cooling in advance with a cooler.Examples of a substance having a high melting point which may be used inthis case include water, alcohol, organic solvent, and surface-activeagent. It should be noted that when a surface-active agent is jetted outfrom the nozzle 40 and becomes attached to particles P, it penetratesthrough an interface between the particles P and the valve element 37 toremove the particles P from the valve element 37. Thus, the particles Pattached to the valve element 37 can be more reliably removed.

Also, a substance such as SiO₂ that never forms defects on a wafer evenwhen it becomes attached to or accumulated on the surface of the wafermay be used as the second substance in liquid or solid form.

FIGS. 5C and 5D are process drawings of a cleaning process carried outin a fourth variation of the substrate processing system according tothe present embodiment. In this variation, the substrate processingsystem has a single-pole electrode plate 44 disposed closer to theloader module 4 than the valve element 37, and the nozzle 40 has anadding unit 45 (removal promoting substance generating unit) disposedpart way therealong, for adding single-pole ions of the reverse polarityto the polarity of the single-pole electrode plate 44 to a gas, therebyproducing a single-pole ion added gas (removal promoting substance).

As shown in FIGS. 5C and 5D, first, before a wafer W is transferred inthe substrate processing system, the nozzle 40 jets out a single-poleion added gas produced by the adding unit 45 toward the valve element 37(FIG. 5C).

Then, particles P attached to the valve element 37 are reliablyscattered away through, for example, a disturbance caused by viscousforce of the jetted single-pole ion added gas and attraction for thesingle-pole electrode plate 44 caused by an electrostatic force producedthrough charging the particles P on the reverse polarity to the polarityof the single-pole electrode plate 44 due to a physical collision ofsingle-pole ions in the single-pole ion added gas, and the scatteredparticles P are attracted to the single-pole electrode plate 44 andenter into the transfer chamber 25 of the loader module 4 (FIG. 5D).

According to the cleaning process of FIGS. 5C and 5D described above,before the wafer W is transferred, the nozzle 40 jets out thesingle-pole ion added gas produced by the adding unit 45 toward thevalve element 37. If particles P are attached to the valve element 37,the particles P are reliably scattered away through, for example, adisturbance caused by viscous force of the jetted single-pole ion addedgas and attraction for the single-pole electrode plate 44 caused by anelectrostatic force produced through charging the particles P on thereverse polarity to the polarity of the single-pole electrode plate 44due to a physical collision of single-pole ions in the single-pole ionadded gas, the scattered particles P are attracted to the single-poleelectrode plate 44 and enter into the transfer chamber 25 of the loadermodule 4, and the particles P having entered into the transfer chamber25 as well as air flowing into the transfer chamber 25 are caused toflow out from the interior of the substrate processing system. Thus, theparticles P attached to the gate valve 39, in particular, the valveelement 37 can be reliably removed, and the particles P can bedischarged from the interior of the substrate processing system.

FIGS. 6A and 6B are process drawings of a cleaning process carried outin a fifth variation of the substrate processing system according to thepresent embodiment. In this variation, the nozzle 40 has aplasma-forming unit 47 (removal promoting substance generating unit)disposed at a distal end thereof, for turning a gas into plasma toproduce ions (removal promoting substance), and the valve element 37 ischarged on the reverse polarity to the polarity of the ions produced bythe plasma-forming unit 47 since a direct-current power source 46(charging mechanism) is connected to the valve element 37. It should benoted that the plasma-forming unit 47 turns a gas into plasma in anenvironment at normal pressure or reduced pressure. Examples of the gasthat is turned into plasma include argon.

As shown in FIGS. 6A and 6B, first, before a wafer W is transferred inthe substrate processing system, the nozzle 40 jets out ions produced bythe plasma-forming unit 47 toward the valve element 37 (FIG. 6A).

Then, particles P including fine particles attached to the valve element37 are reliably scattered away through sputtering caused by the jettedions, and the scattered particles P enter into the transfer chamber 25of the loader module 4 (FIG. 6B).

According to the cleaning process of FIGS. 6A and 6B described above,before the wafer W is transferred, the nozzle 40 jets out the ionsproduced by the plasma-forming unit 47 toward the valve element 37. Ifparticles P including fine particles are attached to the valve element37, the particles P are reliably scattered away through sputteringcaused by the jetted ions, the scattered particles P enter into thetransfer chamber 25 of the loader module 4, and the particles P havingentered into the transfer chamber 25 as well as air flowing into thetransfer chamber 25 are caused to flow out from the interior of thesubstrate processing system. Thus, the particles P including fineparticles attached to the gate valve 39, in particular, the valveelement 37 can be reliably removed, and the particles P can bedischarged from the interior of the substrate processing system.

FIGS. 6C and 6D are process drawings of a cleaning process carried outin a sixth variation of the substrate processing system according to thepresent embodiment. In this variation, the nozzle 40 has aplasma-forming unit 47 (removal promoting substance generating unit)disposed at a distal end thereof, for turning a gas into plasma toproduce radicals (removal promoting substance). It should be noted thatthe plasma-forming unit 47 turns a gas into plasma in an environment atnormal pressure or reduced pressure.

As shown in FIGS. 6C and 6D, first, before a wafer W is transferred inthe substrate processing system, the nozzle 40 jets out radicalsproduced by the plasma-forming unit 47 toward the valve element 37 (FIG.6C).

Then, particles P including fine particles attached to the valve element37 are scattered away through chemical reaction with the jettedradicals, and the scattered particles P enter into the transfer chamber25 of the loader module 4 (FIG. 6D).

According to the cleaning process of FIGS. 6C and 6D described above,before the wafer W is transferred, the nozzle 40 jets out the radicalsproduced by the plasma-forming unit 47 toward the valve element 37. Ifparticles P including fine particles are attached to the valve element37, the particles P are scattered away through chemical reaction withthe jetted radicals, the scattered particles P enter into the transferchamber 25 of the loader module 4, and the particles P having enteredinto the transfer chamber 25 as well as air flowing into the transferchamber 25 are caused to flow out from the interior of the substrateprocessing system. Thus, the particles P including fine particlesattached to the gate valve 39, in particular, the valve element 37 canbe removed, and the particles P can be discharged from the interior ofthe substrate processing system.

In the present variation, if particles P attached to the valve element37 are CF-based deposits, it is preferred that the plasma-forming unit47 produces oxygen radicals.

Although in the present variation, radicals are jetted out to particlesP attached to the valve element 37, and the particles P and the radicalsare caused to chemically react with each other so as to scatter away theparticles P, a highly-reactive gas with a highly-reactive substance suchas ozone or ammonia added thereto may be jetted out to particlesattached to the valve element 37, and particles P and thehighly-reactive substance may be caused to chemically react with eachother so as to scatter away the particles P, or alternatively, particlesP and ultraviolet light may be caused to chemically react with eachother so as to scatter away the particles P.

Moreover, in the substrate processing systems according to the abovedescribed embodiments, the valve element 37 may have therein a coil 49connected to a direct-current power source 48 as shown in FIG. 7A. Bypassing a current through the coil 49 from the direct-current powersource 48, an induced electric field is produced around the valveelement 37. As a result, an electromagnetic stress as a repulsive forcethat separates particles P from the valve element 37 can be caused toact on the particles P attached to the valve element 37, and henceremoval of the particles P can be promoted. Further, since an inducedfield can be produced around the valve element 37, gas around the valveelement 37 can be turned into plasma. In this case, ions and radicals inthe plasma produced around the valve element 37 promote removal of theparticles P.

Moreover, in the substrate processing systems according to the abovedescribed embodiments, the valve element 37 may have therein a heater 50as shown in FIG. 7B. The heater 50 heats the valve element 37. As aresult, a thermal stress as a removal force that removes particles Pfrom the valve element 37 can be caused to act on the particles Pattached to the valve element 37, and hence removal of the particles Pcan be promoted.

Moreover, in the substrate processing systems according to the abovedescribed embodiments, the valve element 37 may have an electrode plate51 embedded in the vicinity of the surface of the valve element 37 asshown in FIG. 7C. A direct-current power source 52 is connected to theelectrode plate 51, and a current is passed through the electrode plate51 from the direct-current power source 52. As a result, anelectrostatic force as a repulsive force that separates particles P fromthe valve element 37 can be caused to act on the particles P attached tothe valve element 37, and hence removal of the particles P can bepromoted.

Moreover, in the substrate processing systems according to the abovedescribed embodiments, there may be a suction nozzle 53 (first suctionmechanism) disposed closer to the loader module 4 than the valve element37, and a suction nozzle 54 (second suction mechanism) disposed closerto the loader module 5 than the valve element 37 as shown in FIG. 7D.The suction nozzles 53 and 54 suck particles P scattered away from thevalve element 37. As a result, the scattered particles P can be reliablydischarged from the interior of the substrate processing system.

1. A substrate processing system including a gate valve that comprises acommunication port that brings an atmospheric transfer chamber and aninternal pressure variable transfer chamber that transfer a substrateinto communication with each other and a valve element that opens andcloses the communication port, comprising: a jetting mechanism adaptedto jet out a removal promoting substance that promotes removal offoreign matter attached to the gate valve toward the valve element fromthe internal pressure variable transfer chamber side, wherein saidjetting mechanism is provided so as to penetrate through a wall memberdefining the communication port, is exposed only at a distal end thereoffrom an end of the wall member to project out into the communicationport, and the distal end is bent toward the valve element.
 2. Asubstrate processing system according to claim 1, wherein said jettingmechanism comprises a removal promoting substance generating unitadapted to generate the removal promoting substance by heating a gas. 3.A substrate processing system according to claim 1, wherein said jettingmechanism comprises a removal promoting substance generating unitadapted to generate the removal promoting substance by applying avibration to a gas.
 4. A substrate processing system according to claim3, wherein the vibration comprises an ultrasonic wave.
 5. A substrateprocessing system according to claim 1, wherein said jetting mechanismcomprises a removal promoting substance generating unit adapted togenerate the removal promoting substance by mixing a first substance ingaseous form and a second substance in one of liquid form and solidform.
 6. A substrate processing system according to claim 2, comprisinga single-pole electrode plate disposed closer to the atmospherictransfer chamber than the valve element, and wherein said jettingmechanism comprises a removal promoting substance generating unitadapted to generate the removal promoting substance by addingsingle-pole ions of a reverse polarity to a polarity of said single-poleelectrode plate to a gas.
 7. A substrate processing system according toclaim 1, wherein said jetting mechanism comprises a removal promotingsubstance generating unit adapted to generate the removal promotingsubstance by turning a gas into plasma.
 8. A substrate processing systemaccording to claim 7, further comprising a charging mechanism adapted toelectrically charge the valve element.
 9. A substrate processing systemaccording to claim 1, wherein the valve element has therein one of acoil, a heater, and an electrode plate.
 10. A substrate processingsystem according to claim 1, further comprising at least one of a firstsuction mechanism disposed closer to the atmospheric transfer chamberthan the valve element, and a second suction mechanism disposed closerto the internal pressure variable transfer chamber than the valveelement.
 11. A substrate processing system according to claim 1, whereinsaid jetting mechanism comprises a nozzle.
 12. A substrate processingsystem according to claim 1, wherein said jetting mechanism jets theremoval promoting substance from the distal end when said jettingmechanism faces the foreign matter attached to an upper edge of thevalve element.